CVE-2026-78209

high

Description

exceljs through 4.4.0 fails to neutralize leading equals, plus, minus, or at signs in cell values written to CSV output. Attackers who can influence exported cell values can inject formulas that execute when the CSV file is opened in a spreadsheet application, potentially exfiltrating data or performing other malicious actions.

References

https://www.vulncheck.com/advisories/exceljs-through-csv-formula-injection-via-unescaped-cell-values

https://github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-9wxc-4rhw-hfrw

https://github.com/exceljs/exceljs/blob/v4.4.0/lib/csv/csv.js#L109-L182

https://github.com/exceljs/exceljs

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-64684

Details

Source: Mitre, NVD

Published: 2026-08-24

Updated: 2026-10-14

Risk Information

CVSS v2

Base Score: 8.5

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:P/A:N

Severity: High

CVSS v3

Base Score: 8.2

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N

Severity: High

CVSS v4

Base Score: 8.4

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N

Severity: High

EPSS

EPSS: 0.0041